The nurse provides a postoperative client with an analgesic medication and darkens the room before the client goes to sleep for the night. The nurse's actions:

The nurse's actions of providing an analgesic medication and darkening the room aim to decrease stimuli from the cerebral cortex. Reduction of environmental stimuli, especially light and noise, from the cerebral cortex, which is an area of arousal, facilitates sleep. By decreasing input to this area, the client is more likely to fall asleep and stay asleep. Choices B, C, and D are incorrect because the scenario does not involve stimulating hormonal changes, influencing the circadian rhythm, or alerting the hypothalamus.